Microfeature devices and methods for manufacturing microfeature devices

ABSTRACT

Microfeature devices, microfeature workpieces, and methods for manufacturing microfeature devices and microfeature workpieces are disclosed herein. The microfeature workpieces have an integrated circuit, a surface, and a plurality of interconnect elements projecting from the surface and arranged in arrays on the surface. In one embodiment, a method includes forming a coating on the interconnect elements of the microfeature workpiece, producing a layer over the surface of the microfeature workpiece after forming the coating, and removing the coating from at least a portion of the individual interconnect elements. The coating has a surface tension less than a surface tension of the interconnect elements to reduce the extent to which the material in the layer wicks up the interconnect elements and produces a fillet at the base of the individual interconnect elements.

TECHNICAL FIELD

The present invention is related to microfeature devices and methods formanufacturing microfeature devices.

BACKGROUND

Conventional microelectronic devices are manufactured for specificperformance characteristics required for use in a wide range ofelectronic equipment. A microelectronic bare die, for example, includesan integrated circuit and a plurality of bond-pads electrically coupledto the integrated circuit. The bond-pads can be arranged in an array,and a plurality of solder balls can be attached to correspondingbond-pads to construct a “ball-grid array.” Conventional bare dies withball-grid arrays generally have solder balls arranged, for example, in6×9, 6×10, 6×12, 6×15, 6×16, 8×12, 8×14, or 8×16 patterns, but otherpatterns are also used.

Bare dies are generally tested in a post-production batch process todetermine which dies are defective. To protect the dies during testingand other post-production processes, a protective coating is formed overthe surface and/or edges of the dies. One drawback of forming theprotective coating on conventional dies is that the coating material caninterfere with the connection between the solder balls and the contactsof a testing device and, accordingly, result in false negative tests andthe loss of good dies. Thus, there is a need to improve the process offorming the protective coating on bare dies.

In other applications, bare dies and various other packaged dies caninclude an underfill layer across the surface of the dies to (a) protectthe dies from moisture, chemicals, and other contaminants, and (b)enhance the integrity of the joint between the individual dies and thecorresponding substrates to which the dies are subsequently attached.The underfill layer can be formed on the die before the die is attachedto the substrate, and the layer typically has a thickness of betweenapproximately 70 and 90 percent of the height of the solder balls on thedie.

One drawback of conventional processes for depositing underfill acrossthe die is that the underfill material also wicks up and may cover thetop of the solder balls. Consequently, the underfill typically does notinclude dielectric filler particles because if the particles were tobecome trapped on the tops of the solder balls, the particles wouldimpair the subsequent electrical connection between the die and thesubstrate. It is, however, desirable to use underfill with fillerparticles because the particles increase the rigidity of the underfillto provide a more robust package. Accordingly, there is also a need toimprove the process of depositing underfill material on dies.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side cross-sectional view of a bare die with atesting device.

FIGS. 2A–2E illustrate stages in a method of manufacturing a pluralityof microfeature devices in accordance with one embodiment of theinvention.

FIG. 2A is a schematic side cross-sectional view of a microfeatureworkpiece after forming a coating on a plurality of conductive balls.

FIG. 2B is a top plan view of the microfeature workpiece afterdepositing protective material across a plurality of dies.

FIG. 2C is a schematic side cross-sectional view of the microfeatureworkpiece after forming a protective layer across the dies.

FIG. 2D is a schematic side cross-sectional view of the microfeatureworkpiece after removing a portion of the coating from the individualconductive balls.

FIG. 2E is a schematic side cross-sectional view of one of themicrofeature devices during testing.

FIGS. 3A and 3B illustrate stages in a method of manufacturing aplurality of microfeature devices on a microfeature workpiece inaccordance with another embodiment of the invention.

FIG. 3A is a schematic side cross-sectional view of the microfeatureworkpiece including a coating extending across the workpiece.

FIG. 3B is a schematic side cross-sectional view of the microfeatureworkpiece after removing the coating from a portion of the conductiveballs.

FIGS. 4A and 4B illustrate stages in a method of manufacturing aplurality of microfeature devices on a microfeature workpiece inaccordance with another embodiment of the invention.

FIG. 4A is a schematic side cross-sectional view of the microfeatureworkpiece and a plurality of sockets for forming a coating on theconductive balls.

FIG. 4B is a schematic side cross-sectional view of the microfeatureworkpiece after forming the coating on the conductive balls.

FIGS. 5A and 5B illustrate stages in a method of manufacturing aplurality of microfeature devices in accordance with another embodimentof the invention.

FIG. 5A is a schematic side cross-sectional view of a microfeatureworkpiece having an underfill layer extending across the dies.

FIG. 5B is a schematic side cross-sectional view of the microfeatureworkpiece after removing a coating from a distal portion of theconductive balls.

FIG. 6 is a schematic side cross-sectional view of a microfeatureworkpiece having a substrate and a redistribution layer in accordancewith another embodiment of the invention.

DETAILED DESCRIPTION

A. Overview

The following disclosure is directed to microfeature devices,microfeature workpieces, and methods for manufacturing microfeaturedevices and microfeature workpieces. The term “microfeature workpiece”is used throughout to include substrates in and/or on whichmicroelectronic devices, micromechanical devices, data storage elements,and other features are fabricated. For example, microfeature workpiecescan be semiconductor wafers, glass substrates, insulated substrates, ormany other types of substrates. The term “microfeature device” is usedthroughout to include microelectronic devices, micromechanical devices,data storage elements, read/write components, and other articles ofmanufacture. For example, microfeature devices include SIMM, DRAM,flash-memory, ASICS, processors, flip chips, ball-grid array chips, andother types of electronic devices or components. Several specificdetails of the invention are set forth in the following description andin FIGS. 1–6 to provide a thorough understanding of certain embodimentsof the invention. One skilled in the art, however, will understand thatthe present invention may have additional embodiments and that theembodiments of the invention may be practiced without several of thespecific features described below.

FIG. 1 is a schematic side cross-sectional view of a bare die 30 and atesting device 90. The die 30 includes a surface 36, a plurality ofsolder balls 40 on the surface 36, and a protective coating 62 on thesurface 36. The testing device 90 includes a plurality of test contacts92 for applying signals to a proximal portion 42 of the solder balls 40to test the die 30. The protective coating 62 wicks up the solder balls40 and forms fillets 63 that cover the proximal portion 42 of the solderballs 40. The fillets 63 can prevent the test contacts 92 fromcontacting the solder balls 40, causing the die 30 to fail the test eventhough the die 30 functions properly. The protective coating 62 canaccordingly result in false negative tests and the loss of good dies.

Several aspects of the invention are directed toward methods of formingprotective layers on microfeature workpieces that reduce the falsenegative tests and loss of good dies described above. The microfeatureworkpieces have an integrated circuit, a surface, and a plurality ofconductive interconnect elements projecting from the surface andarranged in arrays on the surface. For example, the interconnectelements can be solder balls or other conductive balls. In oneembodiment, a method includes forming a coating on the interconnectelements of the microfeature workpiece, producing a layer over thesurface of the microfeature workpiece after forming the coating, andremoving the coating from at least a portion of the individualinterconnect elements. The coating has a surface tension less than asurface tension of the interconnect elements to reduce the extent towhich the material in the layer wicks up the interconnect elements. Thelayer can be an underfill layer or a protective layer and have a surfacetension greater than the surface tension of the coating.

Another aspect of the invention is directed to methods for manufacturingmicrofeature devices. The microfeature devices can have a surface and aplurality of conductive balls on the surface. In one embodiment, amethod includes coating only a proximal portion of the conductive ballsof the microfeature device with a film having a surface tension lessthan the surface tension of the conductive balls, without coating adistal portion of the conductive balls with the film. The method furtherincludes forming a layer over the surface of the microfeature deviceafter coating the proximal portion of the conductive balls.

In another embodiment, a method includes providing a microfeatureworkpiece having a surface and a plurality of conductive ball arrays onthe surface, forming a sacrificial coating on the conductive balls ofthe microfeature workpiece, and producing a layer over the surface ofthe microfeature workpiece after forming the sacrificial coating. Thesacrificial coating has a surface tension less than the surface tensionof the conductive balls. The method further includes removing thesacrificial coating from a distal portion of the individual conductiveballs, cutting the microfeature workpiece to singulate a plurality ofmicrofeature devices, and testing one of the microfeature devices bycontacting the proximal portion of the corresponding conductive ballswith test contacts.

Another aspect of the invention is directed to microfeature devices. Inone embodiment, a microfeature device includes a die having anintegrated circuit and a plurality of bond-pads electrically coupled tothe integrated circuit. The device further includes a plurality ofinterconnect elements projecting from the die and electrically coupledto corresponding bond-pads. The device further includes a sacrificialcoating on at least a portion of the individual interconnect elementsand a layer over the die proximate to the interconnect elements. Thesacrificial coating has a first surface tension and the interconnectelements have a second surface tension greater than the first surfacetension.

B. Embodiments of Methods for Manufacturing Microfeature Devices

FIGS. 2A–2E illustrate stages in a method of manufacturing a pluralityof microfeature devices 110 in accordance with one embodiment of theinvention. FIG. 2A, more specifically, is a schematic sidecross-sectional view of a microfeature workpiece 100 including asubstrate 120 and a plurality of microelectronic dies 130 formed inand/or on the substrate 120. In the illustrated embodiment, theindividual dies 130 include an integrated circuit 132 (shownschematically), an array of bond-pads 134 electrically coupled to theintegrated circuit 132, a first surface 136, and a second surface 138opposite the first surface 136. The microfeature workpiece 100 furtherincludes a plurality of conductive balls 140 arranged in arrays andattached to corresponding bond-pads 134 of the dies 130. The conductiveballs 140 can be solder balls or other conductive elements to provideexternal electrical contacts for the bond-pads 134 of the dies 130. Inother embodiments, the microfeature workpiece 100 may not includemultiple microelectronic dies 130. For example, the microelectronicworkpiece 100 can be a single die, a circuit board, or another substratewith a plurality of conductive ball arrays.

After forming the conductive balls 140 on the bond-pads 134, a coating150 is formed on the conductive balls 140 to inhibit protective layers,underfill layers, or other materials from wicking up the balls 140 insubsequent procedures. In the illustrated embodiment, the coating 150has a first surface tension and the conductive balls 140 have a secondsurface tension greater than the first surface tension. As such, whenanother material is subsequently deposited onto the first surface 136 ofthe dies 130, the coating 150 inhibits the material from wicking up theconductive balls 140. More specifically, because the surface tension ofthe coating 150 is less than the surface tension of the conductive balls140, the coating 150 reduces the distance that the material wicks up theconductive balls 140.

In the illustrated embodiment, the coating 150 encases the individualconductive balls 140 such that a proximal portion 142 and a distalportion 144 of the balls 140 are covered by the coating 150. In otherembodiments, such as those described below with reference to FIGS. 4Aand 4B, the coating 150 may not completely encase the conductive balls140, but rather may cover only a proximal portion of the individualballs 140. The coating 150 may also cover a portion or all of the firstsurface 136 of the dies 130. For example, in the embodiments describedbelow with reference to FIGS. 3A and 3B, the coating 150 covers all ofthe first surface 136 of the dies 130.

The coating 150 can be a sacrificial thin film or monolayer that isformed on the conductive balls 140 by spraying, dipping, vapordeposition, or other suitable processes. For example, in one process, aportion of the individual conductive balls 140 can be dipped into a bathcontaining the coating material such that the surface tension of theundipped portion of the balls 140 pulls the coating material over theentire surface of the balls 140 to encase the balls 140. Suitablecoating materials include Silane solutions, such as Silquest A-1110,Silquest A-171, and Silquest A-187, manufactured by OSi Specialties inSouth Charleston, W. Va. The coating 150 can alternatively include otherpolymeric materials having a lower surface tension than the conductiveballs 140. After the coating 150 is formed on the conductive balls 140,the microfeature workpiece 100 can optionally be heated to at leastpartially cure (e.g., B-stage) the coating 150.

FIG. 2B is a top plan view of the microfeature workpiece 100 with beadsof protective material 160 deposited in a grid across the first surface136 of the dies 130. After forming the coating 150, the protectivematerial 160 can be dispensed onto the first surface 136 of the dies 130between the conductive balls 140. The protective material 160subsequently flows laterally across the first surface 136 and toward theconductive balls 140 to form a generally uniform coating or protectivelayer 162 (shown in FIG. 2C) on the microfeature workpiece 100.Alternatively, the protective layer 162 can be formed on the workpiece100 by spin coating or other suitable processes.

FIG. 2C is a schematic side cross-sectional view of the microfeatureworkpiece 100 after forming the protective layer 162 across the firstsurface 136 of the dies 130. The protective layer 162 protects thedelicate internal components on the front side of the microfeaturedevices 110 during singulation, testing, and other production processes.The protective layer 162 can have a generally uniform thickness T₁across the microfeature workpiece 100. In the illustrated embodiment,the thickness T₁ can be from approximately 5 microns to approximately 30microns; however, in other embodiments, the thickness T₁ can be lessthan 5 microns or greater than 30 microns.

The protective material 160 may have a surface tension that is less thanor greater than the surface tension of the coating 150. In either case,because the surface tension of the coating 150 is less than the surfacetension of the conductive balls 140, the coating 150 reduces wicking ofthe protective material 160 up the conductive balls 140 compared to theextent that the material 160 would wick up the balls 140 without thecoating 150. The coating 150 accordingly reduces the fillet height ofthe material 160 to reduce interference with the subsequent testing ofthe microfeature devices 110, as described below. The surface tension ofthe coating 150 is preferably less than the surface tension of theprotective material 160 to further reduce the distance that the material160 wicks up the conductive balls 140. After forming the protectivelayer 162 on the microfeature workpiece 100, the workpiece 100 can beheated to at least partially cure (e.g., B-stage) the coating 150 andthe protective layer 162.

FIG. 2D is a schematic side cross-sectional view of the microfeatureworkpiece 100 with a portion of the coating 150 removed from theindividual conductive balls 140. After the protective layer 162 isformed across the microfeature workpiece 100, the coating 150 on theportion of the conductive balls 140 projecting from the protective layer162 is removed to expose the surface of the balls 140 for subsequenttesting and/or attachment to a corresponding substrate or other externaldevice. The coating 150 can be removed from the balls 140 via wetetching, plasma etching, or other suitable processes withoutsignificantly reducing the thickness T₁ of the protective layer 162 onthe dies 130. For example, the coating 150 can be removed from theconductive balls 140 with a plasma having 95 percent O₂ and 5 percentCF₄. Before or after removing the portion of the coating 150, themicrofeature workpiece 100 can be cut along the lines A₁—A₁ to singulatethe microfeature devices 110.

FIG. 2E is a schematic side cross-sectional view of one of themicrofeature devices 110 and a testing device 190. After singulation,the microfeature devices 110 can be tested to verify and ensure that thedevices 110 function according to specification. The illustrated testingdevice 190 includes pairs of test contacts 192 for contacting theproximal portion 142 of corresponding conductive balls 140 adjacent tothe protective layer 162 and applying electrical signals to test themicrofeature device 110. For example, a first test contact 192 aincludes a first end 193 a that contacts a first side of the proximalportion 142 of a conductive ball 140 a, and a second test contact 192 bincludes a second end 193 b that contacts a second side of the proximalportion 142 of the conductive ball 140 a. In other embodiments, thetesting device 190 can test the microfeature devices 110 on themicrofeature workpiece 100 (FIG. 2D) before singulation.

One feature of the microfeature devices 110 illustrated in FIGS. 2A–2Eis that the coating 150 reduces the extent to which the protectivematerial 160 wicks up the conductive balls 140 to reduce the height ofthe fillets at the proximal portion 142 of the balls 140. An advantageof this feature is that the elimination of fillets, or at least thereduction in the height of fillets, increases the reliability of thetesting process because the test contacts 192 of the testing device 190can contact the proximal portion 142 of the conductive balls 140 withoutinterference.

C. Additional Embodiments of Methods for Forming a Protective Layer onMicrofeature Devices

FIGS. 3A and 3B illustrate stages in a method of manufacturing aplurality of microfeature devices 210 on a microfeature workpiece 200 inaccordance with another embodiment of the invention. For example, FIG.3A is a schematic side cross-sectional view of the microfeatureworkpiece 200 including a coating 250 extending across the workpiece200. The microfeature workpiece 200 is generally similar to themicrofeature workpiece 100 described above with reference to FIGS.2A–2D. The coating 250 on the workpiece 200, however, covers theconductive balls 140 and the first surface 136 of the dies 130. Thecoating 250 can be formed on the workpiece 200 by spraying, dipping,atomic layer deposition (ALD), chemical vapor deposition (CVD), physicalvapor deposition (PVD), or other suitable processes. After forming thecoating 250, the protective material is deposited onto the coating 250on the first surface 136 to form the protective layer 162. As describedabove, the surface tension of the coating 250 is less than that of theconductive balls 140 to reduce the extent to which the protectivematerial wicks up the conductive balls 140 and produces fillets at theproximal portion 142 of the balls 140.

FIG. 3B is a schematic side cross-sectional view of the microfeatureworkpiece 200 with a portion of the coating 250 removed from theconductive balls 140. After forming the protective layer 162, thecoating 250 on the exposed areas of the conductive balls 140 is removedto expose the surface of the balls 140 for subsequent attachment and/ortesting. The coating 250 on the first surface 136 that is covered by theprotective layer 162 may not be removed. The microfeature workpiece 200can be subsequently cut along the lines A₂—A₂ to singulate themicrofeature devices 210, and the devices 210 can be tested in a processsimilar to that described above with reference to FIG. 2E.

FIGS. 4A and 4B illustrate stages in a method of manufacturing aplurality of microfeature devices 310 on a microfeature workpiece 300 inaccordance with another embodiment of the invention. For example, FIG.4A is a schematic side cross-sectional view of the microfeatureworkpiece 300 and a plurality of sockets 380 for forming a coating onthe conductive balls 140. The microfeature workpiece 300 is generallysimilar to the microfeature workpiece 100 described above with referenceto FIGS. 2A–2D. In the illustrated embodiment, however, the sockets 380form a coating over the proximal portion 142 of the conductive balls 140without forming the coating on the distal portion 144 of the balls 140.More specifically, the individual sockets 380 include a first portion382 and a second portion 384 that selectively clamp together around theproximal portion 142 of the individual conductive balls 140. The firstand second portions 382 and 384 include a sponge-like pliant member 386for carrying the coating material and transferring the material to theconductive balls 140. Accordingly, as the first and second portions 382and 384 clamp together around the conductive balls 140, the first andsecond portions 382 and 384 press the pliant member 386 against thesurface of the conductive balls 140 to deposit coating material onto theballs 140 and form the coating. The first and second portions 382 and384 are sized such that the pliant member 386 forms the coating only onthe proximal portion 142 of the conductive balls 140.

FIG. 4B is a schematic side cross-sectional view of the microfeatureworkpiece 300 after forming a coating 350 on the conductive balls 140and removing the sockets 380 (FIG. 4A). After depositing the coating350, a protective material is deposited onto the first surface 136 ofthe dies 130 to form a protective layer 162 across the microfeatureworkpiece 300. The surface tension of the coating 350 is less than thatof the conductive balls 140 to reduce the extent to which the protectivematerial wicks up the conductive balls 140 and produces fillets at theproximal portion 142 of the balls 140. The exposed portion of thecoating 350 can subsequently be removed so that the test device 190(FIG. 2E) can test the microfeature devices 310. In other embodiments,however, the coating 350 may not need to be removed if the coating 350is sufficiently thin so that the test contacts 192 (FIG. 2E) can applyelectrical signals to the conductive balls 140 through the coating 350.

One feature of the microfeature workpiece 300 illustrated in FIGS. 4A–4Bis that the coating 350 covers the proximal portion 142 of theconductive balls 140 without covering the distal portion 144 of theballs 140. Because the distal portion 144 of the conductive balls 140 isexposed, the coating 350 does not need to be removed to attach the balls140 to a substrate or other external device. An advantage of thisfeature is that the microfeature workpiece 300 may not need to passthrough a cleaning process to remove the coating 350 from the conductiveballs 140 if the coating 350 is sufficiently thin so that the testcontacts 192 can apply electrical signals to the conductive balls 140through the coating 350. Accordingly, the coating 350 can inhibit theprotective material 160 from wicking up the conductive balls 140,without requiring an additional processing step to remove the coating350 from the balls 140.

D. Additional Embodiments of Methods for Forming an Underfill Layer onMicrofeature Devices

FIGS. 5A and 5B illustrate stages in a method of manufacturing aplurality of microfeature devices 410 in accordance with anotherembodiment of the invention. For example, FIG. 5A is a schematic sidecross-sectional view of a microfeature workpiece 400 having an underfilllayer 462 extending across the first surface 136 of the dies 130. Themicrofeature workpiece 400 is generally similar to the microfeatureworkpiece 100 described above with reference to FIGS. 2A–2D. Forexample, the microfeature workpiece 400 has a plurality of conductiveballs 140 and a coating 450 encasing the individual balls 140. Thecoating 450 can also cover the first surface 136 of the dies 130, asdescribed above with reference to FIGS. 3A and 3B. The microfeatureworkpiece 400 can be heated to at least partially cure (e.g., B-stage)the coating 450.

After forming the coating 450, an underfill layer 462 is formed acrossthe first surface 136 of the dies 130. The underfill layer 462 caninclude filler elements 464 to increase the rigidity of the layer 462.The illustrated underfill layer 462 has a thickness T₂ fromapproximately 50 μm to approximately 400 μm and is between approximately70 and 90 percent of a height H of the conductive balls 140.Alternatively, the thickness T₂ of the underfill layer 462 can be lessthan 70 μm or greater than 400 μm and/or a different percentage of theheight H of the conductive balls 140. In any of these embodiments, thesurface tension of the coating 450 is less than the surface tension ofthe conductive balls 140 to reduce the extent to which the underfillmaterial wicks up the conductive balls 140 and covers a distal portion444 of the balls 140. After forming the underfill layer 462, themicrofeature workpiece 400 can be heated to at least partially cure(e.g., B-stage) or solidify the coating 450 and the underfill layer 462.

FIG. 5B is a schematic side cross-sectional view of the microfeatureworkpiece 400 after removing the coating 450 from the distal portion 444of the conductive balls 140 so that the balls 140 can be attached to asubstrate or other external device. The coating 450 on a proximalportion 442 of the conductive balls 140 may not be removed. Afterexposing the distal portion 444 of the conductive balls 140, themicrofeature workpiece 400 can be cut along the lines A₃—A₃ to singulatethe microfeature devices 410. The microfeature devices 410 can be testedby contacting the distal portion 444 of the conductive balls 140 beforeand/or after singulation to verify and ensure that the devices 410function properly.

One feature of the microfeature workpiece 400 illustrated in FIGS. 5Aand 5B is that the coating 450 reduces the extent to which the underfillmaterial wicks up the conductive balls 140. An advantage of this featureis that the underfill layer 462 can include dielectric filler elements464 to increase the rigidity of the layer 462 without the risk that theunderfill material will wick up the conductive balls 140 and fillerelements 464 will become trapped at the distal portion 444 of theconductive balls 140. If filler elements 464 become trapped at thedistal portion 444 of the conductive balls 140, the filler elements 464can impair the electrical connection between the conductive balls 140and the substrate or other external device to which the microfeaturedevice 410 is attached. More specifically, when the individualmicrofeature devices 410 are attached to a substrate, the conductiveballs 140 are coupled to corresponding conductive pads on the substrate.If the filler elements 464 become trapped between the conductive balls140 and the pads, the dielectric filler elements 464 will impair thetransmission of electrical signals between the balls 140 and the pads.

FIG. 6 is a schematic side cross-sectional view of a microfeatureworkpiece 500 having a substrate 520 and a redistribution layer 570formed on the substrate 520 in accordance with another embodiment of theinvention. In the illustrated embodiment, the substrate 520 includes aplurality of microelectronic dies 530 having an integrated circuit 532(shown schematically) and a plurality of bond-pads 534 coupled to theintegrated circuit 532. The redistribution layer 570 includes adielectric layer 572, a plurality of ball-pads 576 in the dielectriclayer 572, and a plurality of conductive lines 578 electrically couplingthe bond-pads 534 to corresponding ball-pads 576. The dielectric layer572 can include several dielectric strata, and the conductive lines 578can include several conductive layers formed between dielectric strata.The ball-pads 576 are arranged in ball-pad arrays relative to themicroelectronic dies 530 such that each die 530 has a correspondingarray of ball-pads 576. The microfeature workpiece 500 further includesa plurality of conductive balls 140 on corresponding ball-pads 576, acoating 450 over a portion of the conductive balls 140, and an underfilllayer 462 over the redistribution layer 570. The conductive balls 140,the coating 450, and the underfill layer 462 are generally similar tothose described above with reference to FIGS. 5A and 5B.

From the foregoing, it will be appreciated that specific embodiments ofthe invention have been described herein for purposes of illustration,but that various modifications may be made without deviating from thespirit and scope of the invention. For example, the coating 250 shown inFIG. 3A can be used with the underfill layer 462 in the embodimentsshown in FIGS. 5A–6, or other elements of any of the foregoingembodiments can be combined with each other in alternative embodiments.Accordingly, the invention is not limited except as by the appendedclaims.

1. A method for manufacturing a microfeature workpiece, the microfeature workpiece having an integrated circuit, a surface, and a plurality of conductive interconnect elements projecting from the surface and arranged in arrays on the surface, the method comprising: forming a coating on at least the interconnect elements of the microfeature workpiece, the coating having a surface tension less than a surface tension of the interconnect elements; producing a layer over the surface of the microfeature workpiece after forming the coating; and removing the coating from at least a portion of the individual interconnect elements.
 2. The method of claim 1 wherein: forming the coating comprises depositing a sacrificial coating onto at least the interconnect elements; and producing the layer comprises depositing a protective layer onto the surface of the workpiece.
 3. The method of claim 1 wherein: forming the coating comprises depositing a sacrificial coating onto at least the interconnect elements; and producing the layer comprises flowing an underfill onto the surface of the workpiece.
 4. The method of claim 1 wherein forming the coating comprises depositing the coating onto the surface of the microfeature workpiece and the interconnect elements.
 5. The method of claim 1 wherein forming the coating comprises depositing a coating including Silane onto the interconnect elements.
 6. The method of claim 1 wherein forming the coating comprises depositing a sacrificial coating onto the interconnect elements.
 7. The method of claim 1 wherein forming the coating comprises dipping at least a portion of the individual interconnect elements into a bath.
 8. The method of claim 1 wherein forming the coating comprises depositing the coating via a vapor deposition process.
 9. The method of claim 1 wherein forming the coating comprises spraying material onto the interconnect elements and the surface of the microfeature workpiece.
 10. The method of claim 1, further comprising heating the coating to at least partially cure the coating before producing the layer.
 11. The method of claim 1, further comprising heating the coating and the layer to at least partially cure the coating and the layer before removing the coating.
 12. The method of claim 1 wherein the layer has a surface tension greater than the surface tension of the coating.
 13. The method of claim 1 wherein producing the layer after forming the coating comprises inhibiting the layer from wicking up the interconnect elements.
 14. A method for manufacturing a microfeature device, the method comprising: providing a microfeature device having a surface and a plurality of conductive balls on the surface, the conductive balls having a first surface tension; coating the conductive balls of the microfeature device with a sacrificial film having a second surface tension less than the first surface tension; forming a layer over the surface of the microfeature device after coating the conductive balls; and removing the sacrificial film from at least a portion of the individual conductive balls.
 15. The method of claim 14 wherein forming the layer comprises depositing a protective layer onto the surface of the device.
 16. The method of claim 14 wherein forming the layer comprises flowing an underfill onto the surface of the device.
 17. The method of claim 14 wherein coating the conductive balls comprises depositing Silane onto the conductive balls.
 18. The method of claim 14 wherein the layer has a third surface tension greater than the second surface tension of the sacrificial film.
 19. A method for manufacturing a microfeature workpiece, the microfeature workpiece having a surface and a plurality of conductive ball arrays on the surface, the method comprising: forming a first coating on at least the conductive balls of the microfeature workpiece to inhibit a second coating from wicking up the conductive balls; producing the second coating over the surface of the microfeature workpiece after forming the first coating; and removing the first coating from at least a portion of the individual conductive balls after forming the second coating.
 20. The method of claim 19 wherein the first coating has a first surface tension and the conductive balls have a second surface tension greater than the first surface tension.
 21. The method of claim 19 wherein the first coating has a first surface tension and the second coating has a second surface tension greater than the first surface tension.
 22. The method of claim 19 wherein: forming the first coating comprises depositing a sacrificial coating onto at least the conductive balls; and producing the second coating comprises forming a protective layer on the surface of the workpiece.
 23. The method of claim 19 wherein: forming the first coating comprises depositing a sacrificial coating onto at least the conductive balls; and producing the second coating comprises flowing an underfill onto the surface of the workpiece.
 24. The method of claim 19 wherein forming the first coating comprises depositing the first coating onto the surface of the microfeature workpiece and the conductive balls.
 25. The method of claim 19 wherein forming the first coating comprises depositing Silane onto the conductive balls.
 26. The method of claim 19, further comprising: cutting the microfeature workpiece to singulate a plurality of microfeature devices; and testing at least one of the microfeature devices by contacting the proximal portion of the corresponding conductive balls on the at least one microfeature device with test contacts.
 27. A method of manufacturing a plurality of microfeature devices, comprising: providing a microfeature workpiece having a surface and a plurality of conductive ball arrays on the surface; forming a sacrificial coating on the conductive balls of the microfeature workpiece, the sacrificial coating having a surface tension less than a surface tension of the conductive balls; producing a layer over the surface of the microfeature workpiece after forming the sacrificial coating; removing the sacrificial coating from at least a distal portion of the individual conductive balls; cutting the microfeature workpiece to singulate a plurality of microfeature devices; and testing at least one of the microfeature devices by contacting a proximal portion of the corresponding conductive balls on the at least one microfeature device with test contacts.
 28. The method of claim 27 wherein producing the layer comprises forming a protective layer over the surface of the workpiece.
 29. The method of claim 27 wherein producing the layer comprises flowing an underfill having filler elements over the surface of the workpiece.
 30. The method of claim 27 wherein forming the sacrificial coating comprises depositing Silane onto the conductive balls.
 31. The method of claim 27 wherein the layer has a surface tension greater than the surface tension of the sacrificial coating. 